A conventional winding machine comprises an upper winding roller, a guide plate, a lower winding roller, and a rider roller. The guide plate is arranged at a location close to and below a circumferential surface of the upper winding roller and forms a channel with the upper winding roller. The upper winding roller, the lower winding roller, and the rider roller form therebetween a winding nip.
A core around which a web material is wound to form a roll of paper is fed by a conveyor to a location beside the upper winding roller and is then pushed by a core inserter into a passage delimited by the guide plate to reach the winding nip where the web material is wound around the core to form the roll of paper, such as a roll of toilet tissue. After completion of the winding operation of a roll of paper, a rotatable arm is controlled to have a speed that is faster or slower than the rotational speed of the upper winding roller in order to induce a speed difference by which the web material is torn and thus separated.
Another known technique uses a method and a structure that realizes separation of web material with physical engagement. For example, a driving arm is positioned against a surface of an upper winding roller arranged in a winding machine to hold down a web material passing through the surface of the upper winding roller. The web material is then torn and thus separated by a pulling force induced by a roll of paper that is formed in a winding nip by wounding the paper around a core.